This post was written by Erin Janssen. The FDA has issued a series of draft guidance documents addressing an abbreviated pathway for biosimilar product development under Section 351(k) of the Public Health Service (PHS) Act, as amended by the Biologics Price Competition and Innovation Act of 2009. These guidances are intended to assist applicants in navigating an abbreviated approval pathway for biologic products that are “highly similar” or “interchangeable: and have no clinically-meaningful differences of purity, potency and safety to an already FDA-licensed biologic product in the U.S. Providing much-needed and long-awaited information, the three draft biosimilar guidances address common questions, and scientific and quality considerations related to an abbreviated development pathway of biosimilars, as follows: •  Biosimilars: Questions and Answers Regarding Implementation of the Biologics Price Competition and Innovation Act of 2009: This draft guidance provides answers to common questions from potential applicants of such biosimilar products, including questions that may arise in the early stages of product development such as how to request meetings with the FDA, how to address differences in formulation from the reference product, and how to request exclusivity. • Scientific Considerations in Demonstrating Biosimilarity to a Reference Product: This draft guidance is intended to assist companies in demonstrating that a proposed therapeutic protein product is biosimilar to a reference product for the purpose of submitting to FDA an application, called a “351(k)” application after the relevant section of the PHS. This draft guidance describes a risk-based “totality-of-the-evidence” approach that the FDA intends to use to evaluate the data and information submitted in support of a determination of biosimilarity of the proposed product to the reference product. As outlined in the draft guidance, FDA has recommended a stepwise approach in the development of biosimilar products. • Quality Considerations in Demonstrating Biosimilarity to a Reference Protein Product: This draft guidance provides an overview of analytical factors to consider when demonstrating biosimilarity between a proposed therapeutic protein product and a reference product for the purpose of submitting a 351(k) application. This includes guidance on analytical studies relevant to assessing similarity and the importance of extensive analytical, physico-chemical and biological characterization in demonstrating that the proposed biosimilar product is highly similar to the reference product notwithstanding minor differences in clinically inactive components. This guidance may also provide useful information to applicants in the development of other proteins, such as those used in in vivo protein diagnostic products. Comments are due by April 16, 2012. The FDA also has announced a May 11, 2012 public hearing to obtain input from a broad group of stakeholders on the draft guidances. The also FDA is interested in obtaining public comments regarding the Agency’s priorities for development of future policies regarding biosimilars.